Honours biology student Emily Rushton researches how the brain controls hunger
Emily Rushton, a fourth-year honours biology student from Stewiacke, NS spent her summer conducting research on how our brains control hunger. Her focus was to understand the complex mechanisms that dictate when we feel full. Pursuing an honours in biology with a passion for neuroscience, Rushton's work has the potential to reshape our understanding of appetite and health.
“My main academic interests have always been in medicine and physiology,” she says. “Working in Dr. Karen Crosby’s lab gave me the opportunity to explore how the brain regulates food intake.”
Rushton’s focus is on two key satiety hormones, cholecystokinin (CCK) and leptin, which are critical players in how our bodies determine when we’ve had enough to eat.
“CCK and leptin both help us feel full,” she explains, “But they work in different ways.”
CCK, released in response to a meal, curbs appetite in the short term, while leptin, produced by fat cells, helps regulate body weight over the long term.
For Rushton, the brain's dorsomedial hypothalamus (DMH) is where the magic happens.
“This region is a hot spot for appetite regulation,” she says. Despite this, it is surprisingly under-researched compared to other brain regions involved in hunger. The DMH has receptors for both CCK and leptin, which piqued the interest of Crosby’s team.
Could these hormones influence the activity of neurons in this part of the brain? The answer is not straightforward, but Rushton’s work is shedding new light on the subject.
“We wanted to see how these hormones influence neuronal activity and communication in the DMH,” she says.
They specifically focused on female rats, a critical point that marks the first time this research has explored sex differences. Rushton and her team record electrical currents and action potentials from live neurons and take baseline measurements of brain activity, then add CCK and leptin to see how the neurons respond.
“It’s delicate work that requires steady hands, patience, and a lot of precision,” she says.
Their findings suggest both hormones independently reduce neuronal communication in the DMH and, when used together, the effect is even more pronounced suggesting they might work through separate but complementary pathways. However, in rats that had fasted for 24 hours, the hormones had a much smaller impact.
The team also expected to see differences between males and females, especially since prior research indicated CCK might have a stronger effect in females, but they were surprised to find no significant differences between the two.
“Understanding how the brain regulates food intake is crucial, especially in the context of obesity,” says Rushton.
Obesity, linked to a range of health issues like diabetes and heart disease, remains a major public health challenge. If scientists can better understand how CCK and leptin regulate appetite, they might be able to develop new treatments for overeating and obesity.
When asked about the most rewarding aspect of her research, Rushton says.
“Contributing to a body of knowledge that could one day help people is an incredible feeling.”
Dr. Karen Crosby, associate professor in biology, who is supervising Rushton’s research, emphasizes the significance of her work.
“Emily is uncovering how these hormones collaborate to impact neuronal activity. Her findings could significantly advance our understanding of human appetite control and pave the way for developing effective treatments for conditions such as obesity”.
Rushton’s experience in the lab has helped her master advanced neurophysiological techniques usually reserved for graduate students and postdoctoral fellows in just a few months, learning to record electrical activity from living neurons. Beyond that, she says she has improved her statistical analysis, communication, and collaboration skills.
Crosby adds, “Emily has gathered a tremendous amount of data, analyzed previous work, and will present her findings at two upcoming conferences. She's been an absolute pleasure to work with, and I'm confident she'll excel in her goal of becoming a physician.”
For students considering a career in research, Rushton confidently advocates the opportunities at Mount Allison.
“This university may be small, but the research happening here is amazing,' she says. “I have had the chance to learn advanced techniques and work alongside inspiring mentors in a supportive environment. If you are passionate about neuroscience, Mount Allison is the place to be.”
